Choosing the light bulb technology that’s right for you

ONCE upon a time, there were just two basic kinds of lighting you could get for your home: fluorescent tubes or incandescent bulbs. You either had a choice of white light or warm ‘yellow’ light from the two, respectively.

In recent years, we have come to see a new kind of technology commonly called ‘energy saving’ but technically known as compact fluorescent lights or CFLs for short. These fit into the common lamp holders used by incandescent bulbs but produce the white light of fluorescent tubes. The also consume less energy than ordinary bulbs.

The latest technology available is what is called light-emitting diodes, or LEDs. These are the kind of technology used in those tiny lights you find in rechargeable lamps on sale in the open market.

We now look at the pros and cons of each of these general types and leave you to make the choice.
LEDs
As said before, these are the latest in lighting technology today. They are not as common as the others, as their advent is only recent, and they cost quite more than the rest. A typical LED uses a fraction of the wattage required to power a bright incandescent bulb, and this makes LEDs more cost-effective over time. A 12-watt LED that puts out 800 lumens of light (lumens are units of brightness for a light source) will cost about seven times less energy charges as a 60-watt incandescent bulb that puts out 880 lumens.

LEDs are also rated to last for tens of thousands of hours, which can translate to decades of use. Compare that with the year or so you typically get out of an incandescent, according to Energy Star and the Illuminating Engineering Society (IES), the independent organisation that created the testing procedures manufacturers use to rate LED lights. However, most LED bulbs have only been commercially available for a few years now, not long enough to see direct proof of their longevity claims.

Also, LED lights don’t “burn out,” the way that incandescents do. Instead, they undergo “lumen depreciation,” gradually growing dimmer over time. The test that the IES uses to determine a bulb’s longevity is known as the LM80, and it calculates how long it will take for an LED to fade noticeably.
Engineers run the bulb for nine months in order to get an accurate measure of the light’s rate of decay, and using those figures, they can calculate the point at which the light will have faded to 70 per cent of its original brightness. This point, known as “L70,” is the current standard in LED longevity. If an LED is rated 25,000 hours, it really means that it will take the bulb 25,000 hours to fade down to 70 per cent brightness.

This isn’t to say that LEDs don’t fail. They definitely do. As with any device, things can always go wrong. Fortunately, more and more LED bulbs come with multi-year warranties for cases of mechanical failure.
CFLs
Before LEDs exploded into the lighting scene, compact fluorescent lights (CFLs) were seen by many as the sure replacement to incandescent lighting.
Despite the fact that CFLs use between one-fifth and one-third the energy of incandescents, and typically save one to five times their purchase price over the course of their lifetime, many people find the whitish light output of CFL bulbs less aesthetically pleasing than the warm, yellow tone of most incandescents. Others say that CFL bulbs that regularly get powered on and off for short periods of time tend to see a significant decrease in life expectancy. So, you’ll want to save them for lighting that you’re going to keep on for longer periods of time. There’s also the common complaint that they often take a second or two after being switched on in order to fully light up.

But with the improvement of CFL technology you can find a variety of colour options, dimmable CFLs, and even “instant-on” CFL bulbs designed to eliminate the delay between flipping the switch and seeing the light.
Dangers
Like all fluorescents, CFLs contain trace amounts of mercury -- typically 3 to 5 milligrams (mg), although some contain less. This creates the potential for pollution when CFL bulbs are improperly disposed of, something that led to a unique environmental argument against the phasing out of incandescents (although, to be fair, this was before LEDs were seen as such a viable option).

The amount of mercury vapour in a standard CFL bulb is about one-hundredth of what you would find in an old-fashioned thermometer. Even in such a small amount, mercury merits a degree of caution, as direct exposure can cause damage to the brain, lungs, and kidneys. That said, if a CFL shatters on your kitchen floor, you don’t need to panic. Just be sure to open a window and let the room air out for 10 minutes, then carefully transfer the glass and dust into a sealable container (and don’t use a vacuum cleaner -- you don’t want to send those chemicals up into the air).

How to tell if a light bulb is efficient
In simple terms, a light bulb is just a device that converts electricity into light. The more light you get per watt of electricity, the more efficient it is. With incandescent bulbs, efficiency is easy to understand because a specific wattage of electricity will always heat a tungsten filament to a specific temperature, which in turn will yield a specific level of light. This means that, generally speaking, one incandescent will be just as efficient (or by today’s standards, inefficient) as another.